1. Technical Field
The present invention relates to material conveyor systems and, more particularly, to a side dump compatible material conveyor system which includes a conveyor support frame, a first conveyor belt mounted on the conveyor support frame, a second conveyor belt mounted on the conveyor support frame extending generally perpendicular to the first conveyor belt with the first conveyor belt extending generally parallel to the direction of travel of the material placer and spreader unit on which it is mounted such that a side dump trailer may travel alongside the material conveyor system and dump material held within the dump tub of the side dump trailer onto the first conveyor belt for transference of the material to the material placer and spreader unit.
2. Description of the Prior Art
There are numerous conveyor systems which have been adapted for use with material placing and spreading devices such as those used in connection with the production of finished roadway surfaces and sub-surfaces, such as concrete and asphalt paving machines. A typical conveyor system of the prior art is shown in FIG. 1 as including a single conveyor belt extending perpendicularly from the placer/spreader unit. Rear discharge trucks approach and dump their materials onto the conveyor belt. However, each time a truck unloads material onto the belt, the belt must be either extended out into the traveled way, or be lowered from a raised position to accept the material from the truck. It is clear that this method takes time due to the belt being extended, then retracted, or lowered then raised. This method also blocks the travel way any time the belt is not in the retracted or raised position.
It is true that this system has performed adequately for a number of years, so long as the amount of material being dumped onto the conveyor belt was strictly controlled and the dump body performing the dump was of a standard dump body type, i.e. a rear dump type of dump body. As can be seen from the illustration of FIG. 1, however, there are numerous deficiencies with this type of arrangement, not the least of which is that the speed of the placer/spreader unit and dump body must be specifically matched or the material being dumped will miss the conveyor belt or the conveyor belt will impact the rear of the dump body causing damage to both units. Furthermore, because the amount of material which can be dumped onto the conveyor belt is restricted by the width of the conveyor belt and the width of the dump body, the transfer of material from the dump body to the placer/spreader unit is slowed, thus retarding the application of the material to the location where it is being placed by the placer/spreader unit. There is therefore a need for an improved material conveyor system for use with placer/spreader units which will increase the efficiency of transfer of material from the dump body to the placer/spreader unit, yet do so in a safe and easily controllable manner.
Numerous types of systems and devices for moving and unloading material are shown in the prior art, including Lambert, U.S. Pat. No. 4,063,656, Lutz, U.S. Pat. No. 5,405,215, and Suhr, U.S. Pat. No. 3,234,862. However, each of these devices include inherent deficiencies which do not completely solve the above-cited problems found in the prior art. Specifically, none of the devices found in the prior art provide a solution to the use of side dump trailers with placer/spreader units. Briefly, a side dump trailer is a longitudinally extended trailer having pivot joints along each side thereof such that the axis of rotation of the dump tub is generally parallel with the frame of the side dump trailer as opposed to generally perpendicular as is the case with rear dump bodies and trailers. The use of side dump trailers is becoming ever more popular as their generally low cost of operation and ease of use allow them to excel at a variety of tasks. However, there is currently no method by which a side dump trailer may easily transfer material held within the dump tub of the side dump trailer to the placer/spreader unit except by merely dumping the material in front of the placer/spreader unit so that the placer/spreader unit passes over the material and spreads it according to the desired spreading and placing characteristics. It has been found that in many situations it is impossible for the side dump trailer to travel in front of the placer/spreader unit due to the previously prepared bed over which the placer/spreader unit is traveling, as the passage of the side dump trailer over that bed will degrade the condition of the bed and render it useless for its intended purpose. There is therefore a need for a material conveyor system which is compatible for use with side dump trailers for transferring material to a placer/spreader unit.
Therefore, an objective of the present invention is to provide a side dump compatible material conveyor system for use with a material placer and spreader unit.
Another object of the present invention is to provide a side dump compatible material conveyor system which includes a conveyor support frame on which first and second conveyor belts are mounted, the frame mounted to the placer/spreader unit or traveling adjacent thereto with the first conveyor belt extending generally parallel to the direction of travel of the placer/spreader unit and the second conveyor belt extending between the end of the first conveyor belt and the area directly in front of the placer/spreader unit.
Another object of the present invention is to provide a side dump compatible material conveyor system which includes the first conveyor belt on which a side dump trailer may dump its load while traveling parallel thereto such that a greater quantity of material may be transferred in a shorter period of time to the conveyor belt and thus to the placer/spreader unit thereby increasing the efficiency of application of the material by the placer/spreader unit.
Another object of the present invention is to provide a side dump compatible material conveyor system which is usable with side dump trailers as they have increased payload capacity of up to twenty-four (24) tons as opposed to the approximate sixteen (16) ton capacity of rear dump units, thus allowing for a substantial increase in productivity with use of the same number of hauling units.
Another object of the present invention is to provide a side dump compatible material conveyor system which includes a first conveyor belt having a length greater than the length of an associated side dump trailer dump tub such that minor variations in relative speed between the material conveyor system and the side dump trailer may be easily accommodated and will not result in spillage and loss of the material during transfer of the material from the side dump trailer to the material conveyor system of the present invention.
Finally, an object of the present invention is to provide a side dump compatible material conveyor system which is relatively simple and durable in construction and is safe and efficient in use.
The present invention provides a side dump compatible material conveyor system operable to function with a material placer and spreader unit which includes a conveyor support frame and a first conveyor belt mounted on the conveyor support frame. A second conveyor belt includes outer and inner ends, the second conveyor belt mounted on the conveyor support frame and extending generally perpendicular to the first conveyor belt with the outer end of the second conveyor belt positioned adjacent one end of the first conveyor belt such that material moved on the first conveyor belt is transferred to the second conveyor belt. Finally, the inner end of the second conveyor belt is positionable in front of a material placer and spreader unit such that material moved on the second conveyor belt towards the inner end thereof is deposited in front of the material placer and spreader unit for placing and spreading of the material.
The side dump compatible material conveyor system as thus described provides several advantages not found in the prior art. For example, because the first conveyor belt extends generally parallel with the direction of travel of the material placer and spreader unit, a side dump trailer may travel alongside the placer and spreader unit while dumping material onto the first conveyor belt, the material then being transferred to the material placer and spreader unit as described above. Also, even in situations where the side dump trailer, the side dump compatible material conveyor system or both are stationary during the dump, the extended length of the first conveyor belt permits the material placer and spreader to continue moving forward during the dump to generally prevent the dumping of excessive material in one location on the first conveyor belt. Furthermore, because the first and second conveyor belts are mounted together on a frame separate from the material placer and spreader unit, the side dump compatible material conveyor system may be mounted on the material placer and spreader unit or may be positioned separately therefrom to permit use of a single side dump compatible material conveyor system with a number of different material placer and spreader units, thus increasing efficiency and reducing the number of material conveyor systems needed for installation of roads and road bed materials. The present invention also is usable for the stockpiling of material in transferring from the side dump trailer to the area for stockpiling. Finally, because the first conveyor belt extends alongside the material placer and spreader unit and preferably has a length exceeding the length of the side dump trailer dump tub, minor variations in speed between the material placer and spreader unit and the side dump trailer will not result in loss of material during the material transfer so long as the directions of travel of the material placer and spreader unit and side dump trailer remain generally parallel. It is thus seen that the side dump compatible material conveyor system of the present invention provides a substantial improvement over those devices found in the prior art.